In a Young's double-slit experiment,$12$ fringes are observed to be formed in a certain segment of the screen when light of wavelength $600 \ nm$ is used. If the wavelength of light is changed to $400 \ nm$,the number of fringes observed in the same segment of the screen is:

$A$ laser light of wavelength $630 \, nm$ is incident on a pair of slits,and the fringe width of the interference pattern produced is $8.1 \, mm$. In another interference pattern produced by a different light,the fringe width is $7.2 \, mm$. Find the wavelength of this second light in $nm$.

In Young's double slit experiment,if the distance between the two slits is halved,then the fringe width will become

In Young's double slit experiment,the separation $d$ between the slits is $2 \ mm$,the wavelength $\lambda$ of the light used is $5896 \ \mathring{A}$,and the distance $D$ between the screen and slits is $100 \ cm$. It is found that the angular width of the fringes is $0.20^\circ$. To increase the fringe angular width to $0.21^\circ$ (with the same $\lambda$ and $D$),the separation between the slits needs to be changed to ...... $mm$.

If the path difference of the point on the screen from two coherent sources is constant, what is the shape of the trajectory of the point on the screen?

The ratio of intensities at two points on the screen in Young's double slit experiment when waves from the two slits have a path difference of $0$ and $\lambda/4$ ($\lambda$ is the wavelength of light used) $(\cos 0^\circ = 1, \cos \pi/2 = 0)$.